(1) Field of the Invention
The present invention relates to an image forming apparatus such as a copier, printer, facsimile machine or the like, in particular relating to an image forming apparatus equipped with an image display operating device capable of displaying plural pages of document images in preview representation.
(2) Description of the Prior Art
Conventionally, there have been recording systems which include a post-processing apparatus that performs stapling and/or other processes on hard copy to be output from an image forming apparatus so as to produce individual complete hard copy after an image forming process.
Conventionally, the image forming apparatus using this kind of recording system has no means for confirming what composition of pages the document images to be handled is made of, so there has occurred the problem that if a hard copy is printed out without reflecting user's intention, the completed copy only exhibits unwanted printout (unintended copy or printout), resulting in no use other than disposal and producing waste of recording paper, developer and power consumption.
To deal with this, recently there has been a proposal of an image forming apparatus including a preview function in order to enable the user to confirm what kind of hard copy is output, by displaying document images on a display screen provided on a control panel of the image forming apparatus.
As a prior art example, there has been a proposal of a system in which document images are displayed pagewise in a slidable manner on a display screen provided for an image forming apparatus so that the user can sequentially check and confirm the document images to be a hard copy (see Patent Document 1).
There is also another disclosed technology in which a hard copy consisting of a plurality of pages is displayed in a three-dimensional representation on a display screen provided for an image forming apparatus so that the user is able to imagine the finished state of the hard copy (see Patent Document 2).
Patent document 1:
    Japanese Patent Application Laid-open 2009-253777Patent document 2:    Japanese Patent Application Laid-open 2007-110677
However, it is the status-quo that the user cannot grasp the concrete concept of the hard copy or cannot imagine the finished state of the hard copy only from the pagewise display of document images on the display screen as in the technology disclosed in Patent Document 1, causing failure to prevent erroneous copies and printout (cut down on the waste of supplies).
Further, the technology disclosed in Patent Document 2 entails the problem that it is impossible to check the details of the page images of the hard copy though the hard copy can be viewed in three dimensions. Further, since recorded surface on which the image is formed is displayed curvedly, there is the problem that it is difficult to check how the page of image being displayed for confirmation is formed on the recording medium.